<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="css/phone.css" media="screen and (max-width:750px)">
    <link rel="stylesheet" href="css/pad.css" media="(min-width:750px) and (max-width: 1200px)">
    <link rel="stylesheet" href="css/pc.css" media="screen and (min-width: 1200px)">
</head>
<body>
    <div></div>
</body>
</html>